Victoria Police Chief Commissioner Graham Ashton has already revealed the force was again looking at whether to launch a criminal investigation into the scandal.

The fresh parliamentary inquiry was sparked by Ombudsman Deborah Glass' March report which found Labor systematically misused $388,000 in parliamentary allowances to partially fund its winning 2014 election campaign, with public-paid electorate staff directed to promote party candidates.

Her evidence on Wednesday reinforced her report, telling the committee decades-old staff pooling arrangements by Victorian Labor made it confusing and difficult to investigate and MPs who signed up seemed to genuinely believe it was within the rules.